Comparative study on the spermicidal activity of organic solvent fractions from hydroethanolic extracts of Achyranthes aspera and Stephania hernandifolia in human and rat sperm

Abstract

Background: This study was conducted to determine the most effective fraction of the hydroethanolic (water:ethanol, 1:1) extracts of Stephania hernandifolia leaves and Achyranthes aspera roots (in a composite manner at a ratio of 1:3, respectively) that will provide maximum spermicidal activity in human and rat spermatozoa out of five different ratios (1:1, 1:3, 1:7, 3:1 and 7:1) that have been studied in pilot experiments.

Study design: n-Hexane, chloroform and ethyl acetate fractions of the hydroethanolic (1:1) extracts of S. hernandifolia and A. aspera were mixed at 1:3. Different concentrations were tested for sperm immobilization, sperm viability, acrosome status, 5'-nucleotidase activity and nuclear chromatin decondensation using human and rat spermatozoa for the selection of the most effective concentration.

Results: Out of three fractions of the hydroethanolic (1:1) extracts of the said plants, the n-hexane fraction was most effective, and the chloroform fraction exhibited minimum activity for this purpose. At a concentration of 0.1 g/mL hexane fraction, all sperm of the human sample were immobilized immediately (within 20 s). In case of the rat sample, all epididymal spermatozoa were immobilized immediately (within 20 s) by treatment with hexane fraction at a concentration of 0.004 g/mL. All human sperm were found to be nonviable within 20 min. The activity of acrosome enzymes was reduced, and significant release of 5'-nucleotidase (a plasma membrane marker) into the surrounding medium was noted after treatment with 0.1 g/mL hexane fraction, indicating that the hexane fraction affected the cytoarchitecture of the sperm plasma membrane. The maximum number of human sperm failed to decondense when treated with 0.1 g/mL hexane fraction, and sperm motility was also irreversible. The hexane fraction was tested in rats as vaginal contraceptive and showed 100% efficacy, indicating its potential for development as vaginal contraceptive.

Conclusion: The findings indicate that, among the different fractions, the hexane fraction of the hydroethanolic extracts of the two plants produced the most effective spermicidal activity and can be considered as vaginal contraceptive.